Features of the use of phosphoric acid against rust

The appearance of rust on the surface of objects, utensils, and equipment is a pressing problem. To solve this problem, phosphoric acid is often used.

This inorganic compound has many advantages, but also has a number of limitations in use.

To achieve the effect and thoroughly clean products from rust stains and deposits, you must follow the instructions for using phosphoric acid for rust.

Will the remedy help?

In its natural form, orthophosphoric acid (H3PO4) is colorless crystals. The 85th aqueous solution is used in everyday life and industry.

This reagent actively interacts with iron oxides and hydroxides. This explains the high effectiveness of orthophosphoric acid against rust.

The converter helps remove corrosive deposits from metal, ceramic, earthenware, and enamel surfaces. That is why it is advisable to use it when cleaning plumbing fixtures, kitchen utensils, industrial equipment, and cars.

In some cases, a chemical is not recommended for use due to low effectiveness or limitations.. The cleaner does not help if the rust layer is too thick. In such a situation, the oxidized surface is first ground and only then treated with a solution.

Phosphoric acid is not suitable for treating acrylic coatings.

Pros and cons of cleaning

Phosphoric acid is a popular and sought-after rust remover.

This is due to several advantages of the reagent:

• high cleaning efficiency;
• ease of use;
• budget cost;
• wide scope of application.

However, when using this inorganic substance, a number of negative aspects are revealed. The existing disadvantages limit the use of the converter and force one to remember precautions.

The most important disadvantages are:

1. Acid and its vapors can irritate mucous membranes, respiratory tract, and eyes.
2. If a pure substance accidentally enters the stomach, nausea, vomiting, and diarrhea occur.
3. Possible appearance of holes when cleaning very thin products from rust.
4. Cannot be used to remove rust from objects coated with acrylic.

How to dilute and use to remove rusty plaque: instructions

The acid is marketed at a concentration of 85%. If only reagent powder is available, it is diluted with water in a ratio of 1:5 or 1:6.

To use concentrated phosphoric acid to remove rust stains, you must first prepare a working solution.

Next, to remove corrosion traces, one of two methods is used: immersion in a converter or applying a solution to the surface.

Immersion cleansing

For small products, the optimal method is complete immersion in phosphoric acid. Detailed instructions require following step-by-step actions:

• the item is cleaned and degreased with detergent and washed with water;
• 85% reagent is diluted in a large container in a proportion of 100-150 g per 1 liter of water;
• the rusty product is placed in the prepared liquid for one hour;
• during soaking, the item is periodically moved or turned over;
• take out the item and rinse it under running clean water;
• prepare a neutralizer from water (50%), butyl alcohol (48%) and ammonia (2%);
• The product is wiped with an alcohol solution, washed with water and dried.

Each stage of work is important, so ignoring it can worsen the result. To avoid cleaning the surface twice, it is recommended to follow the instructions exactly.

To enhance the effect and obtain a durable protective layer, add a special inhibitor “Katapin” (1-2 grams per liter of solution) to the acidic liquid. The additive slows down the process of interaction with unoxidized metal.

Surface application

This method is used in two cases.

1. Firstly, if a large product is covered with rust, for which it is not possible to use the immersion method.
2. Secondly, if there is not enough phosphoric acid available to fill a large container.

The cleaning technique consists of several sequential steps:

• the area with rust is washed with detergent;
• prepare a working solution of orthophosphoric acid;
• apply the converter to the surface of the product;
• stand for two hours to complete the reaction;
• wash the surface with water and dry slightly;
• prepare a neutralizing solution from water and alcohols;
• wipe the cleaned area with a neutralizer;
• rinse again with water and wipe dry.

This is how you clean rust stains:

• home plumbing,
• tile,
• cast iron boilers,
• pipes,
• heating radiators,
• non-removable car parts.

The dilution of the acid and neutralizing solution is carried out according to the same scheme as used in the immersion method.

Precautions when treating surfaces

In small quantities and in a diluted state, orthophosphoric acid does not exhibit toxicity. This substance is allowed to be added to food products. It is present, for example, in Coca-Cola.

However When working with a pure reagent or high concentration solution, safety precautions must be observed. Phosphoric acid is an aggressive substance that irritates the integument, eyes, respiratory and digestive organs.

In extreme cases, burns and poisoning are possible. If the concentrated converter comes into contact with the skin or eyes, immediately rinse the contact areas with plenty of water or saline solution. Do not wipe the skin with napkins or a towel, as this will increase the penetration of the substance into the tissues.

Tips on the topic of the article

To speed up the cleaning process and make work easier, it is recommended to take into account the degree of corrosion, the nature of the surface and other nuances.

Experts advise:

1. Before using a chemical cleaner, it is advisable to first clean off a significant layer of rust with coarse sandpaper, a wire brush, a knife or a grinder.
2. If the surface after cleaning is planned to be coated with varnish or paint, then it is advisable to use not a pure acid solution, but a factory-made orthophosphorus converter containing additional ingredients.
3. With the surface method, the solution is applied only to the area that has been corroded. To protect the intact coating around the stain, cover it with plastic film.
4. When carrying out the cleaning procedure in the apartment, it is necessary to turn on the ventilation and open the windows.
5. Before and after use, phosphoric acid powder and liquid should be stored in hermetically sealed containers at room temperature, on shelves out of reach of children.

Useful video

The video will show you how to remove rust stains using phosphoric acid:

Conclusion

Phosphoric acid is an excellent tool for removing traces of rust on various surfaces. To get the desired effect, you must choose the appropriate cleansing method and strictly follow the instructions for using the converter. In any case, working with chemicals requires compliance with safety rules.